Multiple endocrine neoplasia
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Multiple endocrine neoplasia (MEN) consists of three syndromes featuring tumors of endocrine glands, each with its own characteristic pattern. The presence of any one tumor type does not automatically have a patient labelled as MEN, but a search of the other at-risk areas is usually undertaken, especially when there are suggestive clinical signs.
MEN syndromes are inherited as autosomal dominant disorders. Medullary carcinoma of the thyroid may occur as an autosomal dominant in the absence of other features.
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MEN type 1
Type is also known as Wermer's syndrome after Dr Paul Wermer, who described it in 1954:
- Parathyroid hyperplasia/tumour causing hyperparathyroidism.
- Islet cell tumours causing hypoglycaemia (insulinoma) and Zollinger-Ellison syndrome (gastrinoma).
- Pituitary adenoma which may cause pituitary hormone excess.
The causative mutation is in the menin gene which encodes a nuclear protein, that is believed to act as a tumor suppressor. Most cases of multiple endocrine neoplasia type 1 are inherited in an autosomal dominant pattern.
MEN type 2A and 2B
The next two MEN syndrome types have their basis in molecular genetics. Individuals can be tested for this genetic disorder reliably even when asymptomatic patients. The mutation is in the ret oncogene. Most cases of multiple endocrine neoplasia type 2 are inherited in an autosomal dominant pattern.
MEN type 2A
Type 2A is also known as Sipple syndrome (after the American Dr John H. Sipple, who described it in 1961):
- Medullary carcinoma of thyroid which is associated with increased calcitonin secretion. A test for elevated calcitonin should be done after pentagastrin injection and/or calcium infusion, to ensure that all affected patients are detected.
- Pheochromocytoma
- Parathyroid hyperplasia/tumour causing hyperparathyroidism.
MEN type 2B
This syndrome has no eponym; it was described by Schimke et al in 1968. Originally thought to be a third MEN it is now considered a variant of II, especially after linkage to RET was confirmed.
- Phaeochromocytoma
- Medullary carcinoma of thyroid which is associated with increased calcitonin secretion. A test for elevated calcitonin should be done after pentagastrin injection and/or calcium infusion, to ensure that all affected patients are detected.
- Mucosal neuromas which are usually situated in the gastrointestinal tract.
- Marfanoid habitus
References
- Wermer P. Genetic aspect of adenomatosis of endocrine glands. Am J Med 1954;16:363-371. PMID 13138607.
- Schimke RN, Hartmann WH, Prout TE, Rimoin DL. Syndrome of bilateral pheochromocytoma, medullary thyroid carcinoma and multiple neuromas. A possible regulatory defect in the differentiation of chromaffin tissue. N Engl J Med 1968;279:1-7. PMID 4968712
- Sipple JH. The association of pheochromocytoma with carcinoma of the thyroid gland. Am J Med 1961;31:163-166.
External links
- Template:OMIM (MEN1 & menin gene), Template:OMIM (MEN 2a), Template:OMIM (MEN2b), Template:OMIM (RET gene)de:Multiple endokrine Neoplasie